1 Imagine you are in a submersible. Your mission is to study the ocean from surface to floor. Your job is to measure the density, salinity, temperature, and pressure of the water. You will go through all three layers of the ocean. What will you find?2 The first layer you go through is the surface zone. It is also called the sunlight zone. It goes from the surface to 200 meters below sea level. Sunlight passes easily through the water in this zone. This energy also heats the water.3 Temperatures at the surface are different in different parts of the world. Near the North Pole, the surface temperature is only about twenty-eight degrees Fahrenheit. Near the equator, it can be as high as ninety-seven degrees.4 The salinity of the water is highest in the surface zone. It averages about thirty-five to thirty-seven parts per thousand. This is also the layer with the most life in it. You see many familiar kinds of fish and other marine animals. You also see algae and other kinds of plants.